66400385 has 32 divisors (see below), whose sum is σ = 88843392. Its totient is φ = 47416320.

The previous prime is 66400349. The next prime is 66400403. The reversal of 66400385 is 58300466.

It is a de Polignac number, because none of the positive numbers 2^k-66400385 is a prime.

It is a super-2 number, since 2×66400385² = 8818022256296450, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 134990 + ... + 135480.

It is an arithmetic number, because the mean of its divisors is an integer number (2776356).

Almost surely, 2^66400385 is an apocalyptic number.

It is an amenable number.

66400385 is a deficient number, since it is larger than the sum of its proper divisors (22443007).

66400385 is a wasteful number, since it uses less digits than its factorization.

66400385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 593.

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 66400385 is about 8148.6431385845. The cubic root of 66400385 is about 404.9395530373.

The spelling of 66400385 in words is "sixty-six million, four hundred thousand, three hundred eighty-five".